1. Field of the Invention
The present invention relates to a liquid container for supplying a liquid (ink) to a liquid ejection means used in a variety of printing fields and also to a method of manufacturing the liquid container.
2. Description of the Related Art
Ink jet printing apparatus have an advantage over laser beam printers using a toner as a printing material in that they can easily be reduced in size and weight and constructed inexpensively. Because of this advantage, the ink jet printing apparatus is most suitable as a small output device. In digital cameras of recent years in particular, there are demands that images shot by the cameras be able to be printed out on the spot. To meet this demand ultrasmall ink jet printing apparatus small enough to be mounted on the camera body or carried by user have been proposed and implemented.
Some such ultrasmall ink jet printing apparatus are known to have a construction in which a head cartridge having a liquid ejection means for ejecting ink and a liquid container integrally connected to the liquid ejection means to supply ink to it is removably mounted on a carriage.
The liquid container in the head cartridge can accommodate only a small volume of ink, which is consumed in a short period of time, and thus requires to be supplied frequently with ink. To deal with this problem, an ink jet printing apparatus, which employs a so-called pit-in system has been proposed. In the system a main tank as a liquid source supplies ink to the liquid container.
In the ink jet printing apparatus using the pit-in system, an ink supply to the liquid container is performed as follows. The carriage is moved to a predetermined supply position, which may be at the end of a carriage path. At this position, the liquid container is connected to the main tank and the container is connected to the pomp, as required. Then a negative pressure is created in the liquid container by the pump to draw ink from the main tank into the liquid container by suction.
When ink is replenished in such a pit-in system, an exact predetermined amount of ink must be supplied to the liquid container. This requires that connection and disconnection between a connecting portion of the ink tank and an ink supply member of the liquid container be performed reliably. Further, since the ink supply to the liquid container is performed frequently, a connecting portion between the liquid container and the main tank, particularly the ink supply member, is required to have high durability and reliability.
Generally, the liquid container and the main tank are connected and disconnected by bringing the ink supply member protruding from the liquid container into and out of engagement with a connection member provided at one end of an ink supply tube coming out of the main tank. However, as the connection and disconnection between the ink supply member and the connection member are repeated frequently, the ink supply member may be damaged in a short period of time. That is, since the ink supply member on the liquid container side is bonded to a container body with an adhesive, the bonded portion is subject to bonding strength variations and degradation due to contact with ink, which is likely to result in a joint portion between the ink supply member and the container being damaged.
Once the joint portion of the ink supply member is damaged, the container cannot maintain its air tightness during the pit-in operation, failing to supply an appropriate amount of ink. Further, the ink in the container may leak out from the head cartridge through the damaged joint portion of the ink supply member, contaminating the interior of the apparatus. In some cases, ink may leak out into an entire ink supply system, leading to a fatal electric short-circuit trouble.
Further, the manufacturing method described above requires a quality management system for adhesives used and additional processes, such as adhesive application and hardening processes, increasing cost and number of processes.
The present invention has been accomplished to overcome the above drawbacks and provides a liquid container and a method of manufacturing liquid container which can prevent a possible loss of airtightness in the liquid container and a possible ink leakage to enhance reliability and at the same time can reduce a manufacturing cost and the number of processes.
The above objective is realized by the following aspects of the present invention.
In one aspect, the present invention provides a liquid container for supplying liquid to a liquid ejection means, comprising: a container body containing the liquid; and a cylindrical liquid supply member hermetically secured to an opening formed in a bottom portion of the container body; wherein the opening is thermally fused to the liquid supply member.
The liquid supply member may have a cylindrical portion having a press fit portion to be fitted under pressure into the opening.
Further, the liquid supply member may have: a cylindrical portion having a press fit portion to be fitted under pressure into the opening; and a flange portion protruding outwardly from an outer surface of the cylindrical portion and adapted to engage the bottom portion of the container body when the press fit portion is fitted under pressure into the opening.
Further, the liquid supply member is preferably formed of a heat resisting member.
In another aspect, the present invention provides a method of manufacturing a liquid container for supplying a liquid to liquid ejection means, the method comprising: a press fit step of fitting a cylindrical liquid supply member under pressure into an opening formed in a bottom portion of a container body containing the liquid; and a heating step of heating by predetermined heating means the opening in which the liquid supply member is fitted under pressure by the press fit step; wherein the opening is heated and melted by the heating step to hermetically secure the opening and the liquid supply member together by thermal fusing.
Further, the heating means may be indirect heating means for applying heat to a portion surrounding the opening through the liquid supply member.
Further, the heating means may comprise a light beam generator for radiating a beam of light of a predetermined wavelength to the liquid supply member.
Further, the heating means may be direct heating means for directly applying heat to a portion surrounding the opening.
In the liquid container and head cartridge of this invention constructed as described above, since the container body is melted and directly joined to the ink supply member, the strength of joint between the ink supply member and the container tank and the container airtightness can be improved significantly, compared with the conventional construction in which the container body and the ink supply member are joined by means of an adhesive. This prevents damage to the joint between the ink supply member and the container body even if the connection portion of the main tank is connected to and disconnected from the ink supply member frequently. Thus, an appropriate joint state can be maintained for a long period of time. This in turn enables ink to be supplied properly into the liquid container and eliminates a possibility of ink leaking through the joint between the opening and the liquid supply member. Therefore, it is possible to reliably prevent a contamination of the interior of the printing apparatus with a leaking ink and also an electric system becoming short-circuited.
Further, a quality management system for adhesives and adhesive application and hardening processes are not required, as they are when adhesives are used. This reduces cost and the number of processes.
The above and other objects, effects, features and advantages of the present invention will become more apparent from the following description of embodiments thereof taken in conjunction with the accompanying drawings.